(Paper) Exam Paper AIPMT 2010  Physics
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Q.1. Consider the following two statements:
 Kirchhoff's junction law follows from the conservation of charge.
 Kirchhoff's loop law follows from the conservation of energy
Which of the following is correct?
 Both (A) and (B) are wrong
 (A) is correct and (B) is wrong
 (A) is wrong and (B) is correct
 (4) Both (A) and (B) are correct
Sol:
Junction − conservation of charge Loop − conservation of energy
Answer: (4)
Q. 2. Electromagnets are made of soft iron because soft iron has:
 low retentivity and high coercive force
 high retentivity and high coercive force
 low retentivity and low coercive force
 high retentivity and low coercive force
Answer : (4)
Q. 3. A series combination of n_{1}
capacitors, each of value C_{1}, is charged by a source of
potential difference 4 V. When another parallel combination of n_{2}
capacitors, each
of value C_{2}, is charged by a source of potential difference V, it has
the same (total)
energy stored in it, as the first combination has. The value of C_{2},
in terms of C_{1}, is then:
Sol:
Answer : (4)
Q. 4. The potential difference that must
be applied to stop the fastest photoelectrons
emitted by a nickel surface, having work function 5.01 eV, when ultraviolet
light
of 200 nm falls on it, must be:
 2.4 V
 − 1.2 V
 − 2.4 V
 1.2 V
Sol:
Answer : (4)
Q. 5. Two positive ions, each carrying a
charge q, are separated by a distance d. If F is
the force of repulsion between the ions, the number of electrons missing from
each
ion will be (e being the charge of an electron):
Sol:
Answer : (3)
Q. 6. A block of mass m is in contact with
the cart C as shown in the Figure.
The coefficient of static friction between the block and the cart is μ. The acceleration α of the cart that will prevent the block from falling satisfies:
Sol.
Answer: (3)
Q. 7. A circular disk of moment of inertia is rotating in a horizontal plane, about its symmetry axis, with a constant angular speed . Another disk of moment of inertia Ib is dropped coaxially onto the rotating disk. Initially the second disk has zero Y angular speed. Eventually both the disks rotate with a constant angular speed . The energy lost by the initially rotating disk to friction is:
Sol.
Answer : (4)
Q. 8. The displacement of a particle along the xaxis is given by x = a sin^{2} ωt. The motion of the particle corresponds to:
 Simple harmonic motion of frequency ω/π
 Simple harmonic motion of frequency 3ω/2π
 Non simple harmonic motion
 Simple harmonic motion of frequency ω/2π
Sol.
Answer : (1)
Q. 9. The radii of circular orbits of two satellites A and B of the earth, are 4R and R, respectively. If the speed of satellite A is 3 V, then the speed of satellite B will be:
 3 V/4
 6 V
 12 V
 3 V/2
Sol.
Answer : (2)
Q. 10. A ball is dropped from a high rise
platform at t = 0 starting from rest. After
6 seconds another ball is thrown downwards from the same platform with a speed
v. The two balls meet at t = 18 s. What is the value of v?
 75 m/s
 55 m/s
 40 m/s
 60 m/s
Sol.Distance moved in 18 s by I ball
Distance moved in 12 s by II ball =
Answer : (1)
Q. 11. A ray of light travelling in a
transparent medium of refractive index μ, falls on a
surface separating the medium from air at an angle of incidence of 45O. For
which of the following value of μ the ray can undergo total internal reflection?
 μ = 1.33
 μ = 1.40
 μ = 1.50
 μ = 1.25
Sol :
Answer: (3)
Q. 12. A cylindrical metallic rod in
thermal contact with two reservoirs of heat at its two
ends conducts an amount of heat Q in time t. The metallic rod is melted and the
material is formed into a rod of half the radius of the original rod. What is
the
amount of heat conducted by the new rod, when placed in thermal contact with
the two reservoirs in time t?
2 Q
Sol.
Answer : (2)
Q.13. A transverse wave is represented by
y = A sin (ωt − kx). For what value of the
wavelength is the wave velocity equal to the maximum particle velocity?

A
Sol.
Answer : (3)
Q. 14. An engine pumps water through a hose pipe. Water passes through the pipe and leaves it with a velocity of 2 m/s. The mass per unit length of water in the pipe is 100 kg/m. What is the power of the engine?
 400 W
 200 W
 100 W
 800 W
Sol: Amount of water flowing per second.
Answer : (1)
Q.15. Which one of the following bonds produces a solid that reflects light in the visible region and whose electrical conductivity decreases with temperature and has high melting point?
 metallic bonding
 van der Waal’s bonding
 ionic bonding
 covalent bonding
Sol:
Metal − conductivity decreases with increase in temperature.
Answer : (1)
Q. 16. A conducting circular loop is placed in a uniform magnetic field, B = 0.025 T with its plane perpendicular to the loop. The radius of the loop is made to shrink at a constant rate of 1 mm s^{−1}. The induced e.m.f. when the radius is 2 cm, is:
Sol:
Answer : (2)
Q. 17. A particle of mass M is situated at
the centre of a spherical shell of same mass
and radius a. The gravitational potential at a point situated at a
distance
from
the centre, will be:
Sol : Potential at a point =
Answer : (1)
Q. 18. A tuning fork of frequency 512 Hz
makes 4 beats per second with the vibrating
string of a piano. The beat frequency decreases to 2 beats per sec when the
tension in the piano string is slightly increased. The frequency of the piano
string before increasing the tension was:
 510 Hz
 514 Hz
 516 Hz
 508 Hz
Sol.
Answer : (4)
Q. 19. A galvanometer has a coil of resistance 100 ohm and gives a fullscale deflection for 30 mA current. If it is to work as a voltmeter of 30 volt range, the resistance required to be added will be:
 900 Ω
 1800 Ω
 500 Ω
 1000 Ω
Sol.
Answer : (1)
Q. 20. The energy of a hydrogen atom in the ground state is − 13.6 eV. The energy of a He^{+} ion in the first excited state will be:
 − 13.6 eV
 − 27.2 eV
 − 54.4 eV
 − 6.8 eV
Sol.
Answer : (1)
Q. 21. The dimension of, where ε0 is permittivity of free space and E is electric field, is:
Sol:
Answer : (2)
Q. 22. A man of 50 kg mass is standing in a gravity free space at a height of 10 m above the floor. He throws a stone of 0.5 kg mass downwards with a speed 2 m/s. When the stone reaches the floor, the distance of the man above the floor will be:
 9.9 m
 10.1 m
 10 m
 20 m
Sol: By momentum conservation,
50 u + 0.5 x 2 = 0
Answer : (2)
Q. 23. The total radiant energy per unit area, normal to the direction of incidence, received at a distance R from the centre of a star of radius r, whose outer surface radiates as a black body at a temperature T K is given by:
(Where is Stefan’s constant)
Sol :
Answer : (1)
Q. 24. A common emitter amplifier has a
voltage gain of 50, an input impedance of 100 Ω
and an output impedance of 200 Ω. The power gain of the amplifier is:
 500
 1000
 1250
 50
Sol: Power gain
Answer : (3)
Q. 25. A vibration magnetometer placed in
magnetic meridian has a small bar magnet.
The magnet executes oscillations with a time period of 2 sec in earth’s
horizontal
magnetic field of 24 microtesla. When a horizontal field of 18 microtesla is
produced opposite to the earth’s field by placing a current carrying wire, the
new
time period of magnet will be:
 1 s
 2 s
 3 s
 4 s
Sol: Time period,
Answer : (4)
Q. 26. A square surface of side L meter in
the plane of the paper is placed in a uniform
electric field E (volt/m) acting along the same plane at an angle θ with the
horizontal side of the square as shown in Figure. The electric
flux linked to the
surface, in units of volt. m, is:
 EL^{2}
Zero
Sol:
angle
between E and normal to the surface,
Answer : (4)
Q. 27. A square current carrying loop is
suspended in a uniform magnetic field acting in
the plane of the loop. If the force on one arm of the loop is F, the net force
on the
remaining three arms of the loop is:
Sol:
Force on remaining arms = − F
Answer : (2)
Q. 28. To get an output Y = 1 from the circuit shown below, the input must be:
A B C
 0 1 0
 0 0 1
 1 0 1
 1 0 0
Sol:
A B C Y
0 1 0
0
0 0 1
0
1 0 1
1
1 0 0
0
Input: (1 0 1)
Answer : (3)
Q. 29. A 220 volts input is supplied to a
transformer. The output circuit draws a current
of 2.0 ampere at 440 volts. If the efficiency of the transformer is 80%, the
current drawn by the primary windings of the transformer is:
 3.6 ampere
 2.8 ampere
 2.5 ampere
 5.0 ampere
Sol.
Answer : (4)
Q. 30. In the given circuit the reading of voltmeter V1 and V2 are 300 volts each. The reading of the voltmeter V3 and ammeter A are respectively:
 150 V, 2.2 A
 220 V, 2.2 A
 220 V, 2.0 A
 100 V, 2.0 A
Sol.
Answer : (2)
Q. 31. A lens having focal length f and
aperture of diameter d forms an image of
intensity I. Aperture of diameter d /2 in central region of lens is covered by
a black paper. Focal length of lens and intensity of image now will be
respectively:
Sol: By covering aperture, focal length does not change. But intensity is reduced by
times.
Answer : (3)
Q. 32. An alpha nucleus of energy bombards a heavy nuclear target of charge Ze. Then the distance of closest approach for the alpha nucleus will be proportional to:
Sol:
Answer : (3)
Q. 33. The mass of a Li nucleus is 0.042 u less than the sum of the masses of all its nucleons. The binding energy per nucleon of Li nucleus is nearly :
 46 MeV
 5.6 MeV
 3.9 MeV
 23 MeV
Sol:
Answer : (2)
Q. 34. A beam of cathode rays is subjected to crossed Electric (E) and Magnetic fields (B). The fields are adjusted such that the beam is not deflected. The specific charge of the cathode rays is given by:
(Where V is the potential difference between cathode and anode)
Sol:
eE = eVB
Answer : (4)
Q. 35. A particle has initial velocity
and
has acceleration
.
It
speed after 10 s is:
 7 units
 8.5 units
 10 units
Sol:
Answer : (2)
Q. 36. A particle moves a distance x in
time t according to equation
The acceleration of particle is proportional to:
 (Velocity)^{3/2}
 (distance)^{2}
 (distance)^{−2}
 (velocity)^{2/3}
Sol:
Answer : (1)
Q. 37. Two particles which are initially
at rest, move towards each other under the
action of their internal attraction. If their speeds are v and 2v at any
instant, then the speed of centre of mass of the system will be:
 2 v
 Zero
 1.5 v
 v
Sol: No change in state of motion of COM
due to internal forces.
speed of COM = zero
Answer : (2)
Q. 38. A potentiometer circuit is set up
as shown. The potential gradient, across the
potentiometer wire, is k volt/cm and the ammeter, present in the circuit, reads
1.0 A when two way key is switched off. The balance points, when the key
between the terminals (i) 1 and 2 (ii) 1 and 3, is plugged in, are found to be
at
lengths l1 cm and l2 cm respectively. The magnitudes, of the
resistors R and X, in ohms, are then, equal, respectively, to:
Sol :
P.D arross R = IR =
P.D arross
Answer : (2)
Q. 39. A gramophone record is revolving with an angular velocity ω. A coin is placed at a distance r from the centre of the record. The static coefficient of friction is μ. The coin will revolve with the record if:
Sol.
Answer : (3)
Q. 40. Which of the following statement is
false for the properties of electromagnetic
waves?
 Both electric and magnetic field vectors attain the maxima and minima at the same place and same time
 The energy in electromagnetic wave is divided equally between electric and magnetic vectors
 Both electric and magnetic field vectors are parallel to each other and
perpendicular to the direction of propagation of wave  These waves do not require any material medium for propagation
Answer : (3)
Q. 41. Six vectors,
through
have
the magnitudes and directions indicated in the
figure. Which of the following statements is true?
Answer: (3)
Q. 42. In producing chlorine by electrolysis 100 kW power at 125 V is being consumed. How much chlorine per minute is liberated?
Sol.
Answer : (3)
Q. 43. If ΔU and ΔW represent the increase
in internal energy and work done by the
system respectively in a thermodynamical process, which of the following is
true?
 ΔU = − ΔW, in a adiabatic process
 ΔU = ΔW, in a isothermal process
 ΔU = ΔW, in a adiabatic process
 ΔU = − ΔW, in a isothermal process.
Sol:
ΔQ = ΔU + ΔW
In adiabatic, ΔQ = 0
ΔU = − ΔW
In isothermal, ΔU = 0
Answer : (1)
Q. 44. The device that can act as a complete electronic circuit is:
 Junction diode
 Integrated circuit
 Junction transistor
 Zener diode
Answer : (2)
Q. 45. The activity of a radioactive sample is measured as counts per minute at t = 0 and counts per minute at t = 5 minutes. The time (in minutes) at which the activity reduces to half its value is:
Sol.
Answer : (4)
Q. 46. A thin ring of radius R meter has
charge q coulomb uniformly spread on it. The
ring rotates about its axis with a constant frequency of f revolutions/s. The
value
of magnetic induction in Wb/m^{2} at the centre of the ring is:
Sol .
Answer : (4)
Q. 47. A ball moving with velocity 2 m/s collides head on with another stationary ball of double the mass. If the coefficient of restitution is 0.5, then their velocities (in m/s) after collision will be:
 0, 1
 1, 1
 1, 0.5
 0, 2
Sol.
Answer : (1)
Q. 48. The period of oscillation of a mass M suspended from a spring of negligible mass is T. If along with it another mass M is also suspended, the period of oscillation will now be:
 T


Sol.
Answer : (4)
Q. 49. Which one of the following statement is FALSE?
 Pure Si doped with trivalent impurities gives a ptype semiconductor
 Majority carriers in a ntype semiconductor are holes
 Minority carriers in a ptype semiconductor are electrons
 The resistance of intrinsic semiconductor decreases with increase of temperature
Answer : (2)